Do you know how VoIP works? Put yourself to the test. If your scores are not as high as you you'd like, read SearchUnifiedCommunications.com's How does VoIP work?: A technical guide to functional VoIP and make the VoIP grade.
- How many bits are in a conventional PCM voice sample? Answer
- How is a telephone call on the PSTN usually terminated? Answer
- Give the two basic components of a data message? Answer
- Every data frame or packet carries two components (at least) in the header. What are they? Answer
- In question 4, how does this differ from a PCM frame? Answer
- What is a CRC sequence used for? Answer
- Give at least two different ways the PSTN may setup a voice circuit. Answer
- List at least five drawbacks or challenges designers faced in making VoIP a reality. Answer
- List at least four tasks the gateway may do. Answer
- List at least four transmission media and formats that a media gateway should be able to
support. Answer
- A media gateway interfaces a PSTN PCM bit stream. Give three types of traffic that may be
transported in that bit stream, each requiring some sort of special handling. Answer
- Given an IP packet used for voice transport. Assume G.711 or G.726 coders. How many bytes
(octets) can we expect in the payload? Answer
- Give some data you have learned about one-way delay. What is the one-way delay (in ms) that
should not be exceeded as a design goal? Answer
- What one-way delay (in MS) should never be exceeded? Answer
- What would you say is the biggest contributor to one-way delay? Answer
- What is "look-ahead" used for? Answer
- There is buffer delay. What is its cause and it varies with the number of xxxxx in tandem? Answer
- What is one very obvious way to reduce delay? Answer
- On G.711 circuits, the lost packet rate objective is? Answer
- Give at least two ways to handle the presence of a lost packet. Answer
- What is the basic function of a media gateway controller? Answer
- Give at least three of the four signaling protocol options between an MGC and a media gateway.
Answer
- Give a primary function of an MGC regarding delay using the H.323 protocol on a VoIP circuit.
Answer
- Differentiate RTP and RTCP. Answer
- In the SIP protocol, what are end-users called?Answer
- What are the two modes with which a caller can set up a call with SIP? Answer
- In MGCP gateways are expected to execute commands sent by____. Answer
- Megaco (H.248) is a call-control protocol that communicates between a ____ and a____. Answer
- What are the two basic abstractions relating to the Megaco model? Answer
- A point-to-point connectivity must have at least ___ terminations. Answer
- How are terminations referenced in Megaco? Answer
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This was first published in June 2006